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Can Goldfish Live in Tap Water? Everything You Need to Know!

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By Lindsey Stanton


Goldfish are small, undemanding pets. They’re incredibly easy to care for, making them great for first-time pet owners. Moreover, they’re so cheap and readily available, you could even end up bringing one home from a night at the fair!

So, what should you do when you get your new goldfish home? Is it safe to fill up their aquarium with tap water? The short answer is no. Untreated tap water can actually kill your new goldfish! Let’s take a closer look at the detriments of tap water and look for a feasible solution.

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Toxic Chemicals in Tap Water

Credit: com77380, Pixabay

Tap water undergoes a rigorous treatment process to ensure it’s safe for people to drink. Granted, some places have far better water to begin with, and some places have superior treatment processes. Still, all tap water is being treated, and it’s this treatment that causes the problems for your goldfish.

During the treatment process, water is subjected to many different chemicals that are designed to remove harmful contaminants. While these are considered safe for humans, for the most part, they’re not always safe for goldfish.


Chlorine is one of the most common chemicals used for treating tap water. You’ll find it in high amounts in tap water everywhere. You can even smell the chlorine in some tap water! It’s great for killing off detrimental bacteria such as E-coli so that we can safely drink the water. But chlorine is deadly for a goldfish. It can damage their gills, cause breathing problems, and will even kill the fish with prolonged exposure.


Chloramine is a chemical that’s quite similar to chlorine and many treatment facilities use it instead. Unfortunately, it has essentially the same effects on your goldfish as chlorine. Exposure to chloramine can ruin your fish’s gills and prevent them from breathing properly, eventually, resulting in death.

Heavy Metals

You might be surprised to find out that your tap water is actually infested with heavy metals. You’ll find metals like cadmium, zinc, and mercury in tap water everywhere. In some places, you’ll even find copper and lead. These metals aren’t good for us, let alone a tiny goldfish. They’ll weaken your fish’s immune system, causing high levels of stress that are detrimental to your fish’s health.


Goldfish secrete ammonia. If the concentration of ammonia in your fish tank is higher than your goldfish’s levels, your fish will stop secreting the ammonia, resulting in ammonia poisoning. Since your fish is already releasing ammonia into the water, the ammonia level will be naturally rising. But tap water can contain rather high concentrations of this chemical that can cause the ammonia level in your tank to quickly rise above your fish’s levels.

Safe Water for Your Goldfish

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Credit: imsogabriel, Pixabay

So, if you can’t put your goldfish in tap water, what water can you use?

Basically, you have two options. You can get pre-conditioned water or you can condition the water yourself.

If you need help getting the water quality in your aquarium just right for your goldfish family, or just want to learn more on the subject (and more!), we recommend that you check out our best-selling book, The Truth About Goldfish.

The Truth About Goldfish New Edition

It covers everything from water conditioners to nitrates/nitrites to tank maintenance and full access to our essential fishkeeping medicine cabinet!

Pre-conditioned Water

You can purchase pre-conditioned water at many pet stores. It’s often called treated water. This water is ready to add to your fish tank and won’t require any additional steps. It’s completely safe for your goldfish but can become rather pricey since you’ll be replacing water in your aquarium often.

Water Conditioning

For a more affordable alternative, you can opt to condition the water yourself. In this case, you’d simply add conditioner to tap water. You can get concentrated bottles of water conditioner that treat thousands of gallons affordably. Find the best ones available this year here!

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Can You Boil Tap Water for Goldfish?

If you were in a dire situation where the only water available was contaminated, you’d probably think to boil the water and make it safe to drink. The same thing should work for your goldfish too, right? Think again.

Boiling tap water does remove pathogens and many contaminants from the water, such as bacteria. However, that’s not what poses the biggest threat to your goldfish. The heavy metals, chlorine, and ammonia in tap water will not be removed by boiling it. Your only option is to treat the water with a water conditioner instead.

Can You Keep a Goldfish in Tap Water for the Short-Term?

The moment your goldfish is exposed to contaminated water, their gills will start to be affected. Those heavy metals and chemicals in tap water can cause severe damage quickly. Once your fish’s gills are damaged, you won’t be able to reverse it. Putting your goldfish in tap water will result in death. Likely, within just a few hours.

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Goldfish are incredibly easy to care for. But they’re not particularly hardy creatures. The wrong chemicals can easily damage a goldfish’s gills and cause immeasurable damage to their health. Unfortunately, those chemicals are common in tap water, so, you’ll want to avoid ever putting your goldfish in tap water for any length of time. Death is almost certain to result.

Featured image credit: Arcaion, Pixabay

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